Abstract
The emergence of novel drugs and the continuous expansion of the scope of the types of drugs under control have greatly increased requests for screening of a range of drugs in hair. Here, a multi-analyte method for the detection and quantification of 88 psychotropic drugs in the hair of addicts in drug abstinence was developed and fully validated using liquid chromatography-tandem mass spectrometry (LC-MS-MS). Hair samples (25 mg) were washed, cut into pieces, cryogenically ground and extracted in methanol. The extracted analytes were separated on an Allure PFP Propyl column (100 × 2.1 mm, 5 mm inside diameter, Restek, USA) and analyzed by LC-MS-MS in multiple reaction monitoring modes. The limits of detection and the limits of quantification ranged from 0.1 to 20 pg/mg and 0.2 to 50 pg/mg, respectively. The intra- and inter-assay precisions (relative standard deviation (RSD)) of all analyses ranged from 0.9% to 14.9% and 1.9% to 15.9%, respectively. Accuracy values were 100 ± 20%. The extraction recovery of quality control samples ranged from 50.9% to 99.6% for all analytes. The matrix effects for all analytes ranged from 46.8% to 99.7%. The method was successfully used to analyze 1,865 hair samples from addicts in drug rehabilitation at their own communities. Among the samples, 129 cases were positive; the majority of positive cases were from males (78.29%), 92.25% of whom were >35 years old. Traditional drugs, like methamphetamine and opioids, accounted for most positive cases, and 27 of the abstinence cases with a use history of methamphetamine were still positive. In addition to abused drugs, like methamphetamine, morphine and cocaine, the sedative-hypnotic and psychotherapeutic drugs, including clonazepam, alprazolam, estazolam, zolpidem and quetiapine, were detected in 26% of the hair samples, suggesting that these addicts may have insomnia and mental problems such as depression and psychosis, probably due to the long-term effects of drugs and withdrawal reactions. Three synthetic cannabinoids were also detected in four (2.7%) cases. A total of 37 cases were positive for methadone, tramadol and dextromethorphan, reflecting a new trend of alternative drug use when traditional drugs were not easy to obtain during the coronavirus disease 2019 outbreak.